With regard to the first point, devices are currently made that have addressed the problem of sealing off the distribution disk during closing from the internal wall of the container by means of plastic material or by inserting a rubber gasket in the area in which the container wall comes into contact with the distribution disk. In both cases there are nevertheless seal problems in the area where the shaft joins the disk because it is controlled by an organ outside the container. In addition, if the seal is provided by a disk made of plastic material, clear wear problems arise, which are less marked in the case of seals provided by rubber gaskets, but the latter have to be frequently dismantled for cleaning, which is anyway necessary when the product being treated is changed, because of the fixing system of the gasket, which comprises fittings consisting of mechanical connecting organs on which dust often collects.
With regard to the second aspect, we have attempted to transfer material from one container to another without its coming into contact with the external atmosphere, by giving each of the two containers its own independent distribution organ. This ensures that the insides of the containers that are to be connected to one another are opened only after they have been connected. To protect the internal space between the connection sleeves and their valves from dust, dust caps are fitted to the sleeves, these caps, obviously, must be removed before connecting and this has the grave disadvantage of bringing the front spaces of the two containers into contact, albeit for a short time, with the external atmosphere and therefore making it possible for dust to settle.
In order to avoid this disadvantage a double-disk check device has been fitted: the check organ of the receiving container, by means of external control, is arranged with the bottom surface on the same level as the flange's connecting surface; the same thing happens with the top surface of the check organ of the transfer container in relation to the surface of its own connection flange, except that the latter does not have any control organ but carries out the rotary opening movement only if it is impelled by the other organ after the two containers have been connected. In this way the surfaces that have been contaminated by contact with the external atmosphere should not cause any disadvantages because they come into contact with one another and not with the internal atmosphere that thus remains sterile. This method of procedure nevertheless does not guarantee freedom from contamination, because contamination may arise, for example, from imperfect adherence of the two surfaces, which could cause, although to a minimal degree, dust to enter the inside of the containers.